What best describes the relationship between heart rate and time during exercise?

The relationship between heart rate and time during exercise is typically characterized by an initial increase in heart rate as physical activity begins, reflecting the body's increased demand for oxygen. This heart rate generally stabilizes at a steady state during moderate-intensity exercise. As exercise continues, particularly at higher intensities, the heart rate may rise further, depending on the individual's fitness level and the demands of the activity. Ultimately, recovery occurs post-exercise, with heart rate gradually returning to baseline levels.